4 files changed, 28 insertions, 37 deletions

diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index d13ee7683..e05b370b1 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -274,11 +274,8 @@ static int finish_test(struct child_test *child_test, int width)
 	struct test_suite *t = child_test->test;
 	int i = child_test->test_num;
 	int subi = child_test->subtest;
-	int out = child_test->process.out;
 	int err = child_test->process.err;
-	bool out_done = out <= 0;
 	bool err_done = err <= 0;
-	struct strbuf out_output = STRBUF_INIT;
 	struct strbuf err_output = STRBUF_INIT;
 	int ret;
 
@@ -290,11 +287,9 @@ static int finish_test(struct child_test *child_test, int width)
 		pr_info("%3d: %-*s:\n", i + 1, width, test_description(t, -1));
 
 	/*
-	 * Busy loop reading from the child's stdout and stderr that are set to
-	 * be non-blocking until EOF.
+	 * Busy loop reading from the child's stdout/stderr that are set to be
+	 * non-blocking until EOF.
 	 */
-	if (!out_done)
-		fcntl(out, F_SETFL, O_NONBLOCK);
 	if (!err_done)
 		fcntl(err, F_SETFL, O_NONBLOCK);
 	if (verbose > 1) {
@@ -303,11 +298,8 @@ static int finish_test(struct child_test *child_test, int width)
 		else
 			pr_info("%3d: %s:\n", i + 1, test_description(t, -1));
 	}
-	while (!out_done || !err_done) {
-		struct pollfd pfds[2] = {
-			{ .fd = out,
-			  .events = POLLIN | POLLERR | POLLHUP | POLLNVAL,
-			},
+	while (!err_done) {
+		struct pollfd pfds[1] = {
 			{ .fd = err,
 			  .events = POLLIN | POLLERR | POLLHUP | POLLNVAL,
 			},
@@ -317,21 +309,7 @@ static int finish_test(struct child_test *child_test, int width)
 
 		/* Poll to avoid excessive spinning, timeout set for 1000ms. */
 		poll(pfds, ARRAY_SIZE(pfds), /*timeout=*/1000);
-		if (!out_done && pfds[0].revents) {
-			errno = 0;
-			len = read(out, buf, sizeof(buf) - 1);
-
-			if (len <= 0) {
-				out_done = errno != EAGAIN;
-			} else {
-				buf[len] = '\0';
-				if (verbose > 1)
-					fprintf(stdout, "%s", buf);
-				else
-					strbuf_addstr(&out_output, buf);
-			}
-		}
-		if (!err_done && pfds[1].revents) {
+		if (!err_done && pfds[0].revents) {
 			errno = 0;
 			len = read(err, buf, sizeof(buf) - 1);
 
@@ -354,14 +332,10 @@ static int finish_test(struct child_test *child_test, int width)
 			pr_info("%3d.%1d: %s:\n", i + 1, subi + 1, test_description(t, subi));
 		else
 			pr_info("%3d: %s:\n", i + 1, test_description(t, -1));
-		fprintf(stdout, "%s", out_output.buf);
 		fprintf(stderr, "%s", err_output.buf);
 	}
-	strbuf_release(&out_output);
 	strbuf_release(&err_output);
 	print_test_result(t, i, subi, ret, width);
-	if (out > 0)
-		close(out);
 	if (err > 0)
 		close(err);
 	return 0;
@@ -394,6 +368,7 @@ static int start_test(struct test_suite *test, int i, int subi, struct child_tes
 		(*child)->process.no_stdout = 1;
 		(*child)->process.no_stderr = 1;
 	} else {
+		(*child)->process.stdout_to_stderr = 1;
 		(*child)->process.out = -1;
 		(*child)->process.err = -1;
 	}
diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
index 7a3a7bbbe..29d2f3ee4 100644
--- a/tools/perf/tests/code-reading.c
+++ b/tools/perf/tests/code-reading.c
@@ -637,11 +637,11 @@ static int do_test_code_reading(bool try_kcore)
 
 		evlist__config(evlist, &opts, NULL);
 
-		evsel = evlist__first(evlist);
-
-		evsel->core.attr.comm = 1;
-		evsel->core.attr.disabled = 1;
-		evsel->core.attr.enable_on_exec = 0;
+		evlist__for_each_entry(evlist, evsel) {
+			evsel->core.attr.comm = 1;
+			evsel->core.attr.disabled = 1;
+			evsel->core.attr.enable_on_exec = 0;
+		}
 
 		ret = evlist__open(evlist);
 		if (ret < 0) {
diff --git a/tools/perf/tests/shell/test_arm_coresight.sh b/tools/perf/tests/shell/test_arm_coresight.sh
index 65dd85207..3302ea0b9 100755
--- a/tools/perf/tests/shell/test_arm_coresight.sh
+++ b/tools/perf/tests/shell/test_arm_coresight.sh
@@ -188,7 +188,7 @@ arm_cs_etm_snapshot_test() {
 
 arm_cs_etm_basic_test() {
 	echo "Recording trace with '$*'"
-	perf record -o ${perfdata} "$@" -- ls > /dev/null 2>&1
+	perf record -o ${perfdata} "$@" -m,8M -- ls > /dev/null 2>&1
 
 	perf_script_branch_samples ls &&
 	perf_report_branch_samples ls &&
diff --git a/tools/perf/tests/workloads/datasym.c b/tools/perf/tests/workloads/datasym.c
index ddd40bc63..8e08fc75a 100644
--- a/tools/perf/tests/workloads/datasym.c
+++ b/tools/perf/tests/workloads/datasym.c
@@ -16,6 +16,22 @@ static int datasym(int argc __maybe_unused, const char **argv __maybe_unused)
 {
 	for (;;) {
 		buf1.data1++;
+		if (buf1.data1 == 123) {
+			/*
+			 * Add some 'noise' in the loop to work around errata
+			 * 1694299 on Arm N1.
+			 *
+			 * Bias exists in SPE sampling which can cause the load
+			 * and store instructions to be skipped entirely. This
+			 * comes and goes randomly depending on the offset the
+			 * linker places the datasym loop at in the Perf binary.
+			 * With an extra branch in the middle of the loop that
+			 * isn't always taken, the instruction stream is no
+			 * longer a continuous repeating pattern that interacts
+			 * badly with the bias.
+			 */
+			buf1.data1++;
+		}
 		buf1.data2 += buf1.data1;
 	}
 	return 0;